A double mobility prosthetic cup is a type of acetabular implant that is designed to increase a patient's range of hip mobility. Unlike other types of acetabular implants, double mobility prosthetic cups do not have an opening through the cup portion which allows for easy manipulation during implantation. For example, a rod is typically threaded through the cup opening to the apex of the cup dome where there is typically a threaded hole. This rod is used like a handle with which to control and guide the implant during implantation. Double mobility implants, on the other hand, do not have such an opening and therefore create a challenge in controlling them during implantation. The present invention solves this problem and provides an effective novel means of manipulating the double mobility implant during implantation.
Complicated mechanical devices have crevices and recesses that are difficult, if not almost impossible to clean with ease. Devices that are not properly cleaned and sterilized run the risk of disease transfer from patient to patient following the emergence of certain “prions” that are not killed by normal hospital sterilization and need to be physically removed by washing and rinsing.
During implantation of the prosthetic cup, a great amount of mechanical force is delivered to the cup implant. Generally, an impacting force is delivered to the proximal end of the impactor which is then imparted to the prosthetic cup at the distal end. The application of such mechanical impacting forces could damage the implant cup, particularly a double mobility prosthetic cup implant since these types of cup implants generally lack the mechanical strength to withstand the application of impaction forces throughout the prosthetic cup. Furthermore, these double mobility prosthetic cups are precisely machined with smooth surfaces. As such, the machined surfaces of these implants could become structurally deformed, cracked or scratched during implantation. In addition, many double mobility prosthetic cups may comprise an insert liner, commonly made of a ceramic material, that is positioned along the interior surface within the cavity of the prosthetic cup. These inserts provide a protective barrier that allows for smooth movement between a metallic joint and the metallic prosthetic cup. Like the prosthesis cup, these inserts could also become structurally deformed, cracked or scratched during implantation. Such damage to the cup and/or cup insert could result in a decrease of mobility for the patient or the need to repeat the prosthetic cup implantation process. Damage could also increase the risk of higher wear rates for the bearing components leading to possible earlier device failure.
Further, in surgical procedures in which access to the treatment site is limited, it is difficult to use current impactors without subjecting the patient to repeated abrasion and tissue trauma when inserting, operating and extracting surgical instruments.
Still further, once the appropriate position of the implant is selected, it is often difficult to ensure that the position does not change upon insertion of the assembly through the incision.
What is needed, therefore, is a double mobility implant impactor that minimizes the potential of damaging the cup implant during implantation. Further, the present invention provides an impactor that is easily adjustable, operatable, disassemblable, and cleanable. Still further, what is needed is an impactor that enables the surgeon to better maneuver, position and install the double mobility implant in a particular angular orientation.